SUPPLEMENTS: SCIENCE OR SCAM?
The vitamin industry is a multi-billion dollar business, which has given rise to a sometimes uneasy mix of science and money.
Health Agenda magazine
When it comes to the supplement market, the water is murky. It’s believed that 7 in 10 Australian adults self-medicate with supplements, from herbal remedies to nutraceuticals (a blending of nutrient and pharmaceutical) so it’s an issue a lot of Australians want clarity on.
Dr Ken Harvey, Adjunct Associate Professor at Monash’s Department of Epidemiology and Preventive Medicine in Victoria is a crusader against poor practice in, and regulation of, our multi-billion-dollar complementary medicine (CM) industry.
He says it’s not that he’s anti-complementary medicines, he’s pro-science. He’d like manufacturers to invest in and rely upon solid research and well-constructed clinical trials to develop products based on a foundation of good scientific practice. At the moment, he is one of a number of scientists who say the CM industry is using specific, narrow or indeterminate findings to justify more extensive claims of broad, scientifically proven benefits.
On the other hand, ask a complementary medicine practitioner and they’d say Dr Harvey's looking at the picture the wrong way around: people are more focused on their health now than at any time in the past and are more willing to take measures to influence it themselves.
Need for scrutiny
The earnings potential in the CM sector is strong, both here and overseas. A recent report by American research house Future Market Insights showed the global dietary supplements market – including sports nutrition – is expected to grow from US$123 billion to US$251 billion by 2025, driven by growth in China.
The report came with a caveat warning that “factors such as negative publicity and false product claims are expected to hinder overall growth.” And there has been some negative publicity, including reports finding widespread adulteration and contamination of store-branded supplements, with some even testing negative for the active ingredients listed on their labels. An Australian study identified problems including undisclosed ingredients, contaminants, substituted plants and added pharmaceutical agents (including allergy-causing antibiotics).
Another concern is the lack of awareness around the very real risks of dangerous interactions between supplements and medications – with research showing that half of American adults who use supplements do so without input from their healthcare professionals, and an Australian study found that less than half of people taking supplements mentioned this to their GP or on hospital admission.
Assistant Professor of Medicine at Harvard Medical School, Dr Cohen found this troubling, given that “during the past two decades, a steady stream of high-quality studies evaluating dietary supplements has yielded predominantly disappointing results about potential health benefits, whereas evidence of harm has continued to accumulate… Supplements are essential to treat vitamin and mineral deficiencies but for the majority of adults they’re likely provide little if any benefit.”
Health or harm?
In Dr Cohen’s own Harvard Medical School web-published ‘Supplements: A Scorecard’ – is a shortlist of those it considers worthwhile: calcium, vitamin D and fibre, though it notes that for most people there are natural sources of each that are preferable.
Beyond that, it declares disappointing results or possible harmful side effects, save in specific cases of dietary deficiencies, for B vitamins (with the exception of folate for pregnant women), antioxidants (vitamins A, C, E, beta carotene), multivitamins, glucosamine and chondroitin, saw palmetto, niacin, St John’s wort, melatonin and selenium. It issues a stern ‘not recommended’ for zinc, echinacea, DHEA, chromium, ginseng, gingko biloba and many more.
Such warnings-off aren’t just about saving money. Overloading can lead to hypervitaminosis (abnormally high storage levels of vitamins). Too much vitamin C can cause diarrhoea. Too much zinc can cause nausea and contribute to impaired immunity and low levels of HDL (‘good’) cholesterol. Too much iron can cause gastrointestinal upset, nausea, fatigue and significant liver problems. Selenium overdose can lead to gastrointestinal upset, hair loss, fatigue and nervous system problems.
The biggest worry is vitamin A. This vitamin is easily accumulated in the body’s fatty tissue and liver, and excess intake can lead to nervous system, liver, bone and skin disorders and, for pregnant women, birth defects, with significant overdoses being fatal.
Even at recommended levels, the science isn’t supportive. A 2011 US study found that older women who took supplemental multivitamins over 2 decades died at rates higher than those who didn’t (though those who took supplemental calcium had reduced risks). In the same week, JAMA published a Cleveland Clinic study of more than 35,000 American men over a 7-12-year period showing healthy subjects who took vitamin E had an increased risk of prostate cancer.
It’s important to point out that studies to show whether or not the relationship between the supplement and harms is direct have not been done, just as there are few that have been done to back up the CM health claims.
This is largely due to money. Research is costly and the academic dollar is tightly stretched. Complementary Medicines Australia (CMA) Chief Executive Carl Gibson points out that CM companies actually have disincentives to research. This is because the vitamins, herbs and minerals they work with are almost always already in the public domain so there is no intellectual property protection. Despite this, local CM brands have invested heavily in research in recent years, both their own and development departments and in partnership with Australian universities and scientific institutions.
However Dr Harvey explains, whether CM or non-CM many clinical trials that are commercially sponsored tend to have problems with funding bias. The reality is that non-private funding is best, but is limited and research budgets need to be funded somehow.
In an attempt to reduce funding bias, the World Medical Association has proposed a tool through its Declaration of Helsinki, which asks that every trial be registered and have its results reported. An international science-based lobby group, AllTrials, is agitating governments to have the declaration adopted worldwide. This would mean that trials that showed something didn’t work or did harm could no longer be buried – good news for consumers all round.
In Australia, the duty of regulating complementary medicines falls to the TGA, which is part of the Department of Health. As most CM are deemed low risk, they only need to be listed on the Australian Register of Therapeutic Goods which is has a less rigorous process.
Dr John Skerrit, National Manager of the TGA, defended the administration’s work in an episode of Four Corners, “The products have to be from facilities that have been inspected and approved by us,” he said. “They can only contain ingredients that are permitted, so the safety and the quality is there. And … they can only make certain claims about indications, so they can't cure cancer, they can't fix arthritis, they can't fix asthma, they can make general claims about wellbeing.”
Of the many thousands of goods on the market, most haven’t been tested. In the 2015–16 financial year, 408 products were assessed – a staggering 80% were noncompliant, though most infractions were unlikely to cause harm to users, involving labelling, advertising and exaggerated claims of evidence.
Dr Cohen and Dr Harvey agree that the system would benefit from tighter regulations and a framework. "We should create a regulatory framework that permits pills to be promoted for human health only when there is robust evidence to support those claims,” said Dr Harvey.
In 2015 the system came under the scrutiny of the Department of Health’s ‘Review of Medicines and Medical Devices Regulation’, with a panel of medical experts receiving 26 recommendations concerning the regulation of supplements. Dr Harvey isn’t holding his breath though, “Not much has happened with 17 previous reviews since 2002… If we’re to get more good complementary medicines we need to provide incentives for good trials, and we need a logo or a symbol on them that tells the public that it works.”
Dr Skerrit agrees with Dr Harvey on this point, explaining that the TGA is advocating for reforms that highlight evidence-based complementary medicines in the form of an indication – like a symbol – that consumers can look out for.
Are they worth it?
You should always consult a health practitioner to discuss your particular medical and healthcare needs as symptoms may relate to broader health conditions. Also chat to your doctor about the individual risks and benefits of each supplement.
Signs of deficiencies that could require supplements
Vitamin D: bone and joint pain, increased incidence of falls and broken bones (especially in the elderly). Sensible sun exposure can help.
Iodine: lethargy, feeling cold, dry skin, difficulty concentrating, unusual weight gain, constipation.
It's found in dairy, seafood, seaweed and iodised salt.
Fibre: tiredness, constipation and weight gain can all be signs you need more fibre in your diet. Adding fruit and vegetables may be a better long term option.
Calcium: wheezing, muscle aches, dry skin, osteoporosis, brittle nails (usually coupled with vitamin D deficiency). Good dietary sources include dairy, leafy greens and beans.
Vitamin B12: pins and needles, joint pain, depression, irritability (vegans are most commonly deficient in B12). It occurs naturally in shellfish, oily fish, red meat and dairy.